Method and apparatus for collecting recording and displaying data pertaining to an artifact

ABSTRACT

A new and useful method and apparatus are provided for collecting, recording and displaying data pertaining to artifacts in a time based fashion. The apparatus includes a data measurement device such as a GPS receiver or other measurement device for collecting data such as position information pertaining to artifacts, a memory for recording collected data and a user interface having an input for receiving recorded information such as qualitative information pertaining to artifacts from the user and a display for displaying the collected data as it is collected by a user. The user interface includes a time scale to associate the data collected pertaining to the artifacts with the time at which the data was collected providing a useful project management tool for the user as well as for management personnel supervising the user and for providing an accurate time based archival record of data pertaining to artifacts such as their location and physical condition.

This is a continuation of application Ser. No. 08/618,105, filed Mar.19, 1996, now U.S. Pat. No. 5,731,997.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to user interfaces forinformation collection devices and, more particularly, to a datacollection device configured to collect, store and display informationin relation to the time at which the information is collected.

2. Background

A user interface is something which bridges the gap between a human userwho seeks to control a device and the hardware and/or software whichactually controls the device. The familiar keypad of a touch tonetelephone and the alphanumeric keyboard associated with a personalcomputer are such user interfaces. In addition to hardware components,graphical user interfaces have become an increasingly common feature ofpersonal computers. Such interfaces are provided either as built-inportions of the computer operating system, as in the case of theMacintosh computer available from Apple Computer Inc. of Cupertino,Calif., or as add-on software products that can be purchased separately.

Regardless of whether the user interface is a hardware device or asoftware program (or, as is increasingly the case, a combination ofboth), the purpose of the user interface is, as indicated, to bridge thegap between the human operator and the device being utilized. Forexample, graphical user interfaces used with personal computers oftenhave the ability to initiate execution of other, so-called,"applications programs". Examples of application programs might bespreadsheets, word processing programs, database programs, etc. Theprocess of initiating execution of an application program is typicallyhandled through the use of small graphical symbols known as "icons". Thegraphical user interface displays the icons on the computer screen, oneicon for each application program that can be run. The human userinitiates execution of an application program by selecting thecorresponding icon, most often using a pointing device such as a mouse.

A conventional graphical user interface such as described abovesignificantly reduces the amount of information that a user must recallin order to effectively use the computer. For example, instead ofremembering the name of an application program, and the location of theprogram on a particular disk, the user need only remember that aparticular icon is associated with the application program.

Like their graphical counterparts, hardware user interfaces also allowfor ease of operation. For example, the familiar mouse associated with apersonal computer allows a user to position the cursor and select fromamong the various icons displayed on a screen. By using the mouse theuser is able to avoid having to perform a number of complex keystrokes.

An example of a user interface of potentially immense utility is inconjunction with a data collection device used by a field worker whilecollecting information in remote location. For example, surveyingproperty to record information on features such as boundaries andartifacts located on the property could be facilitated with a convenientuser interface. Collecting information while out on a data collectionproject by using any means other than electronic collection devicesrequires extensive note taking in journals or maps that makes itcumbersome to perform the collection and recording task.

It is often useful to be able to record data and notes on electronicdevices such as portable computers, notebooks, or simple electronicrecording devices to simplify the effort a field worker must perform torecord data. The data collected can then be stored for later retrievalby a parent system that can be used to disseminate and interpret thedata into useful information for decision making. In many of theseapplications, a time based record of the data collected would be quiteuseful for tracking factors such as productivity of the data collectingtechnicians, the qualities related to changing data over time as well asother factors. Data collecting devices that incorporate measuringinstruments such as land surveying devices known as Total Stations,Laser range-finders, direction finding beacons, compasses, tape measuresand other such devices would be greatly improved if they had thecapability of noting the time when the date it was collected.

A surveying device that collects data pertaining to artifacts located onreal property such as trees and buildings as well as to boundaries, bothnatural and artificially defined would be greatly improved by a devicethat was able to collect, display and record data with reference to thetime at which the data was collected. If available in real time theinformation could then be used by the operator in the field to track thedata collection to ensure an organized and complete survey. Theinformation could also be used by the operator as well as managementoverseeing the operator to modify the operator's operation for higherefficiency by reducing the time required to collect data as well asorganizing and keeping track of data collected. Furthermore, theinformation would be a useful archival record of a property's physicalhistory. The introduction of advanced geographic location systems suchas a global positioning system could add another dimension to the surveyoperator's capability.

The global positioning system (GPS) is a multiple satellite based radiopositioning system in which each GPS satellite transmits data thatallows a user to precisely measure the distance from selected ones ofthe GPS satellites to his or her receiver antenna and, thereafter, tocompute position, velocity, and time parameters to a high degree ofaccuracy using known triangulation techniques. The signals provided bythe GPS satellites can be received both globally and continuously.

In general, each GPS satellite transmits signals on two frequenciesknown as L1 and L2. The signals are transmitted using spread spectrumtechniques that employ two types of spreading functions. Courseacquisition (C/A) and precise (P) pseudorandom noise (PRN) codes aretransmitted on frequency L1 and the P code only is transmitted onfrequency L2. The C/A code is available to any user, military orcivilian, however, the P code is available only to authorized militaryand civilian users. Both the P and C/A codes contain data that enable areceiver to determine the range between a selected satellite and theuser. Superimposed on both the P and the C/A codes is the navigationmessage. The navigation message contains GPS system time; a hand overword used in connection with transitioning from C/A code to P codetracking; ephemeris data for the particular satellite being tracked; andalmanac data for all the satellites in the GPS constellation.

GPS finds use in a wide variety of applications, including space, air,sea and land vehicle navigation, precise positioning, time transfer,attitude reference, surveying, etc. Within these various disciplines, anumber of prior GPS receivers are known. These include sequentialtracking receivers, continuous reception receivers, multiplexingreceivers, all-in-view receivers, time transfer receivers, and surveyingreceivers.

GPS receivers typically comprise a number of subsystems. These includean antenna assembly, an RF assembly, and a GPS processor assembly. Theantenna assembly receives the L-band GPS signal and amplifies it priorto insertion into the RF assembly. The RF assembly mixes the L-band GPSsignal down to a convenient intermediate frequency (IF). Then, usingvarious known techniques, the PRN code modulating the L-band signal istracked through code correlation to measure the time of transmissions ofthe signals from the satellite. The Doppler shift of the received L-bandsignal is also measured through a carrier tracking loop. The codecorrelation and carrier tracking functions can be performed using eitheranalog or digital processing means.

The control of the code and carrier tracking loops is provided by theGPS processor assembly. By differencing this measurement with the timeof reception, as determined by the receiver's clock, the pseudo rangebetween the receiver and the satellite being tracked may be determined.This pseudo range includes both the range to the satellite and theoffset of the receiver's clock from the GPS master time reference. Thepseudo range measurements and navigation data from four satellites areusually sufficient to compute a three-dimensional position and velocityfix, to calibrate the receiver's clock offset, and to provide anindication of GPS time.

In some known receivers, the receiver processor controller functions areperformed using a computer separate from that on which the navigationfunctions are performed. In other known receivers, both types offunctions are performed by a single processor. Regardless of the systemused, the receiver processor controller functions typically includemonitoring channel status and control, signal acquisition andreacquisition, code and carrier tracking loops, computing pseudo rangeand delta range measurements, determining data hedge timing, acquisitionand storage of almanac and ephemeris data broadcast by the satellites,processor control and timing, address and command decoding, timedinterrupt generation, interrupt acknowledgment control, and GPS timing.

Known GPS receivers also perform navigation processing functionsincluding satellite orbit calculations and satellite selection,atmosphere delay correction calculations, navigation solutioncomputation, clock bias and rate estimates, computation of outputinformation, and preprocessing and coordinate conversion of aidinginformation.

The GPS standard positioning service provides a navigation accuracy of100 meters. A number of applications of GPS (including surveying)require higher levels of accuracy. Accuracy can be improved using atechnique known as differential GPS. This technique involves operating aGPS receiver and a known location. The receiver is used to computesatellite pseudo range correction data using prior knowledge of thecorrect satellite pseudo ranges, which are then broadcast to users inthe same geographic area. The pseudo range corrections are incorporatedinto the navigation solution of another GPS receiver (a remote receiver)to correct the observed satellite pseudo range measurements, therebyimproving the accuracy of the position determination of the remote.Correlation of the errors experienced at the reference station and atthe remote is dependent upon the distance between them, however they arenormally highly correlated for a user within 350 kilometers of thereference station.

As indicated above, GPS receivers have been used to aid in the surveyingprocess. In the past, a surveyor could take a GPS receiver into thefield, position the receiver's antenna at a desired location, switch onthe receiver to gather position data for the given location, andultimately arrive at a location fix for the position of the GPSreceiver's antenna. Very often, such surveying techniques are carriedout in conjunction with city planning operations, such as the monitoringof the condition of city assets, often referred to in the trade asartifacts, for example, utility poles, manhole covers, etc. Thus, asurveyor could position his GPS receiver antenna over a manhole coverand determine a location fix for the manhole cover and other informationof interest. At the same time, the surveyor could record in a fieldnotebook the condition of the manhole cover. Collecting data pertainingto the artifacts is referred to in the profession as "capturing" theartifacts. Later, in an office setting, the position information couldbe correlated with the condition information for the manhole cover andsimilar results for other city artifacts could be combined together toproduce an overall report for the city engineers or other interestedpersons regarding the location and condition of the manhole covers.

The above process is not only time consuming, but there exists thedanger that the surveyor's notebook will be lost or the data will not beaccurately transferred from the notebook to the report. For example,location data associated with one artifact may be improperly associatedwith attribute information for a different artifact. Accordingly, a needexists for a single surveying apparatus which can compile and associateposition information for an artifact of interest together with otherattribute information in the field environment. A user interface wouldalso be useful in helping the surveyor in the field to organize thesurvey logistics as well as the data collected.

For the surveying process discussed above, it would be useful to theuser as well as managing personnel to record in a time based record theevents of a particular survey using a helpful user interface that canstreamline the process of collecting data for a series of artifacts. Itwould be useful to have a record of not only what was surveyed, but alsothe time that was spent on each artifact recorded in the field. Duringthe data collection activities, the surveyor in the field could knowwhether enough time has passed to achieve the proper accuracy ofposition for a given artifact. Furthermore, particular surveys could beinvestigated regarding whether enough time was spent at a particularartifact in order to achieve the proper accuracy of position, whethertoo much time was wasted in gathering useless information, or whether aparticular surveyor in the field is properly performing his duties. Itwould also be useful to give the surveyor in the field a real time mapto refer to in order help keep track of the survey project as a whole.In combination with the time based record, the field worker could evenbacktrack and take new measurements of artifacts that were inaccuratelygathered at an earlier point in time. The time based information couldalso serve as a useful archival record of changing conditions in asurveyed field over time. As will be seen in the specification below,the present invention addresses these needs in a novel and elegantmanner.

SUMMARY OF THE INVENTION

The present invention in one embodiment provides a new and useful deviceand method for collecting data and for recording and displaying timebased information collected during a field study. In a more specificembodiment, the present invention provides a survey device and method ofcollecting data pertaining to land surveying such the geographiclocation of artifacts located on a land area using GPS technology andrelated conditions of the artifacts. The device includes a GPS datagathering device for gathering location data of artifacts in the field.The device includes a microprocessor for processing the positioninformation in a format that can be displayed on a user screen. The timebased information is generated by the device using a clock thatgenerates timing information recorded by the survey device in parallelwith the position information as it is gathered by a user. Whenassociated together, the clock output and the position information allowthe device to generate a Time Line on a display that displays iconsrepresenting artifacts and the time which they were surveyed. Using theposition information, the device generates a map display showing theartifacts on the map as they are gathered. Both the Time Line displayand the map display are recorded by the device as they are created forposterity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a surveying apparatus of the present invention;

FIG. 2 is a depiction of the Time Line display in accordance with oneembodiment of the present invention;

FIG. 3 is a depiction of the map display in accordance with oneembodiment of the present invention;

FIG. 4 is a depiction of an icon library in accordance with oneembodiment of the present invention;

FIG. 5 is a depiction of the capture note display in accordance with oneembodiment of the present invention;

FIG. 6 is a depiction of the scale map display including auto panfeatures in accordance with one embodiment of the present invention;

FIG. 7 is a depiction of the feature layers display including featurelayers in accordance with one embodiment of the present invention;

FIG. 8 is a depiction of the scaling mechanism for the time line windowdisplay in accordance with one embodiment of the present invention;

FIG. 9 is a flow diagram illustrating the steps to open a file inaccordance with one embodiment of the present invention;

FIG. 10 is a flow diagram illustrating the steps to record a feature inaccordance with one embodiment of the present invention;

FIG. 11 is a flow diagram illustrating the steps to record a note inaccordance with one embodiment of the present invention;

FIG. 12 is a flow diagram illustrating the steps that the survey devicetakes in updating the information on the time display while time passesduring the survey in accordance with one embodiment of the presentinvention;

FIG. 13 is a flow diagram illustrating the steps to close a file inaccordance with one embodiment of the present invention;

FIG. 14 is a flow diagram illustrating the steps necessary to pan theTime Line in accordance with one embodiment of the present invention;

FIG. 15 is a flow diagram illustrating the steps necessary to zoom theTime Line in accordance with one embodiment of the present invention;

FIG. 16 is a flow diagram illustrating the steps necessary to select afeature in the Time Line in accordance with one embodiment of thepresent invention;

FIG. 17 is a flow diagram illustrating the steps necessary to select afeature in the map or feature editor in accordance with one embodimentof the present invention;

FIG. 18 is a flow diagram illustrating the steps necessary to draw aTime Line from a file in accordance with one embodiment of the presentinvention;

FIG. 19 is a flow diagram illustrating the steps necessary to draw afeature from a file in accordance with one embodiment of the presentinvention;

FIG. 20 is a depiction of the Time Line display showing the GPS PDOPheuristic in accordance with one embodiment of the invention;

FIG. 21 is a depiction of the Time Line display showing the number ofsatellites in accordance with one embodiment of the invention;

FIG. 22 is a depiction of the Time Line display showing the satellitesused to compute GPS positions in accordance with one embodiment of theinvention;

FIG. 23 is a depiction of the Time Line display showing satelliteelevations in accordance with one embodiment of the invention; and

FIG. 24 is a depiction of the Time Line display showing GPS positionprecision heuristics in accordance with one embodiment of the invention.

DETAILED DESCRIPTION

A survey device is provided for collecting data pertaining to artifactslocated on land areas and boundaries of the land areas. In the followingdescription, many specific details are set forth, such as variouscomputer components, in order to provide a thorough understanding of thepresent invention. It will be appreciated, however, by those skilled inthe art, that the present invention may be practiced without suchspecific details. In other instances, well known control structures andencoding techniques have not been described in detail in order not tounnecessarily obscure the present invention. Also, although a particularembodiment is disclosed in the discussion below and illustrated in thedrawings of FIGS. 1 through 19, it will be appreciated by those skilledin the art of data collection technology, that the present inventiondescribed in the description and shown in the drawings, when read inlight of the background set forth above and within the scope of theclaims, can also be implemented using a variety of data gatheringdevices such as the GPS device described below, surveying devices knownas Total Stations, LASER range-finders, direction finding beacons,compasses, tape measures and other data collection devices withoutdeparting from the spirit and scope of the present invention.

One embodiment of the present invention provides a Time Line window ofdisplay illustrating a chronological view of artifacts surveyed in thefield along with their pertinent features and associated recorded notes.Referring to FIG. 1, survey device 10 includes a keypad 12 for receivinginput from a user. This keypad communicates with the survey device 10via a general purpose input/output (I/O) controller 14 that sendsinformation through the bus 16. A system clock 18 sends signals tosystem bus 16 for recording and display. A microprocessor 20 is providedto control the survey device by communicating with other units via bus16. The survey device 10 also includes a display 22 for displaying aFine Line display to the user while collecting and recording data. Thesurvey device also includes a non-volatile memory 24 and a main memory26. The survey device is also a data collection device that includes aGPS receiver 28 also communicating with the other units via bus 16. Itwill be appreciated that the operating system software and othersoftware needed for operation of survey device 10 will be loaded intothe non-volatile memory 24 prior to use. Non-volatile memory 28 may alsoinclude other start up code to be executed by microprocessor 20 on powerup.

GPS receiver 28 comprises a number of sub-systems familiar to thoseskilled in the art. This includes an antenna assembly, an RF assembly,and a GPS processor assembly. In other embodiments, microprocessor 20may perform some or all of the functions of the GPS processor assembly.In general, GPS receiver 28 operates as a typical GPS receiver. That is,the antenna assembly receives the L-band GPS signals and amplifies thesesignals prior to insertion into the RF assembly. The RF assembly mixesthe L-band GPS signal down to an intermediate frequency. Then, usingvarious known techniques, the PRN code modulating the L-band signal istracked to measure the time of transmission of the signal from the GPSsatellite. The Doppler shift of the received L-band signal may also bemeasured through a carrier tracking loop. These functions may beperformed using either analog or digital processing and, as indicated,may be performed by microprocessor 20.

GPS receiver 28 may function as a differential GPS receiver. As such,GPS receiver 28 may, in addition to receiving signals from GPSsatellites, receive signals from a base station (not shown) operating ina known location. GPS receiver 28 will use the signals from the basestation to compute satellite pseudo range correction data usingtechniques well known in the art. The pseudo range corrections will beincorporated into the navigation solution derived from the GPS satellitesignals, thereby improving the accuracy of the position determination.

Alternatively, GPS receiver 28 could be a GPS translator. In such anembodiment, GPS receiver 28 would include only the antenna assembly andRF assembly portions of a standard GPS receiver. In such a case, theposition calculation determination could be made by microprocessor 20or, could be made at a base station (not shown). For the remainder ofthe discussion which follows, however, it will be assumed that GPSreceiver 28 functions as a standard GPS receiver and makes the requiredposition calculations.

In one embodiment, surveying device 10 comprises a self contained unitwhich is easily transportable. Ideally, surveying device 10 can beeasily carried into the field for use by surveyors. As will be describedbelow, keypad 12 and I/O controller 14 comprise one embodiment of a userinterface for surveying device 10. The interface serves as a userinterface for surveying device 10 and allows an operator to control theoperation of surveying device 10 as described below.

Referring now to FIG. 2 and subsequent figures, a preferred method ofsurveying using surveying device 10 will be described. Upon reviewingthe details of this method, however, others skilled in the art willrecognize that the display window of FIG. 2 and subsequent figuresrepresent only one embodiment of the apparatus and method of the presentinvention and will further recognize that various modifications to thesteps described could be implemented without departing from the spiritand scope of the invention.

Referring to FIG. 2, an example of how a Time Line display can be set upto display relevant data to the user is shown including notes 30, timebars 32, point features such as trees and telephone poles 34, linefeatures representing boundaries 36, area features representing closedboundaries, nested point features 40 that are captured while capturing aline or area feature, local time 42 and other features. The horizontalaxis 44 of the Time Line display represents the sequential passage oftime and each recorded feature and note 30 is displayed above this axisin the appropriate position according to the time in which they werecaptured during a survey. Features and notes appear on the Time Linewindow as icons that a user designates as pertaining to a particularartifact. Notes pertaining to an artifact appear at the point in timewhen they were crested, whereas features appear with an indication ofthe period of time during which they were captured as shown by the timebars 46.

The Time Line window can display both static and dynamic information.Static information can consist of notes and features which havepreviously been recorded in a data file, whereas dynamic information canconsist of features which are currently being recorded.

The chronological view of data provided by the Time Line window displayof FIG. 2 is complementary to the spatial view of the data displayed bythe map window display of FIG. 3. The contents of these two windows aresynchronized, so that a selected object in one window display will alsobe selected in the other.

The time axis and scale appear along the bottom of the Time Line window,with time advancing from left to right. The word "Start" 48, just abovethe time axis, indicates the beginning of the displayed data file. Thereis a corresponding "End" 50, if the file was captured previously and hasbeen opened for viewing or editing only. If the file is newly created orhas been opened for appending, then the word "Now" (not shown) willappear on the Time Line to indicate the current point in time; in thiscase the word "End" will not appear.

Each recorded feature is indicated in two ways: firstly with a "timebar", which indicates the period of time which elapsed between thestarting of the feature and the ending of the feature, and secondly withan icon for point features, a line for line features or a rectangle forarea features. The symbol or icon displayed for each type of pointfeature can be configured by the user, and is the same as the symboldisplayed on the Map window for that feature type. Icons can be selectedfrom an icon library as shown in FIG. 4. For example, the tree featuresin the sample Time Line of FIG. 1 appear with a tree icon. The colorused for line and area features can similarly be configured by the userand matches the color used for displaying these features on the Mapwindow of FIG. 3. For example, the area feature 38 in the sample TimeLine of FIG. 2 represents a pond represented as a closed line area andcan appear in blue on a colored display.

Features appear on the Time Line in two layers, as the survey devicesoftware allows the user to record one or more point features within aline or area feature. This action, called "nesting", avoids the need torecord an entire line or area feature and then backtrack to record anypoints of interest which appeared along that line or area. The sampleTime Line of FIG. 2 illustrates a "tree" feature 40 which was nestedinside a "curb" feature 36. A multitude of variations on this theme arepossible.

The note making display is illustrated in FIG. 5. Notes appear at thetop of the Time Line window, as in note 30 in FIG. 2, in the form oficons that can be prompted to display recorded text. The time at which anote was entered determines the point at which it appears in the TimeLine indicating the exact time the note was taken during the survey. Theuser can configure the icon used to represent a note.

The steps necessary to open a new or existing data file are illustratedin the flow diagram of FIG. 9. When a new or existing data file isopened by the survey device, while the Time Line display is also open,each feature and note which appears in the data file will be drawn intothe Time Line display at the appropriate location. The time at which thedata file was created will be indicated with the word "Start". If thedata file was opened for viewing only, then the word "End" will alsoappear at the point in time where the last item was appended to the datafile. The method of drawing the time line from a file is discussed belowin relation to FIG. 17.

If a new or existing data file is opened for appending, then the word"End" will not appear in the Time Line display. Instead, the word "Now"will appear at the current point in time, and this will advance alongthe Time Line moving towards the right as time progresses. Thus, word"Now" indicates the current time.

The steps necessary for recording a feature are illustrated in flowdiagram of FIG. 10. When the user starts to capture a feature, the TimeLine begins to display a "time bar" from the moment in time that thefeature first appears on the display. This "time bar" extends from thatpoint to the word "Now", which indicates the current point in time. Astime progresses, the "time bar" dynamically grows to indicate thepassage of time.

When the user completes recording the feature or artifact, after havingdescribed its attributes and, if it is a line feature, having physicallytraversed the feature, the survey device displays either the iconassociated with the feature if it is a point feature)or a line-rectanglein the configured color if it is a line/area feature. From this pointon, the feature's "time bar" stops progressing with passing time and theword "Now" continues to progress to the right, indicating the continuedpassage of time. This process is discussed below with reference to FIG.13.

If a user initiates a "nested" point feature while the user is recordinga line or area feature, the point feature's "time bar" will appear abovethe line/area feature, and the line/area feature's "time bar" alsocontinues to grow. When the nested point feature is recorded, theappropriate icon for that feature is displayed as described above andits associated "time bar" stops growing. The line/area feature's "timebar" continues to grow until the line/area feature is stopped. It ispossible to nest many point features within a line or area feature. Thisis accomplished by using the Feature Layers display shown in FIG. 7.

The user can manipulate the information displayed in the Time Linewindow in a number of ways such as panning, zooming, scaling, selectingfeatures to be included on the timeline and interacting with a twodimensional map display that records location data pertaining tofeatures recorded on the Time Line display.

FIG. 11 illustrates the steps necessary to record a note pertaining tothe survey. Once "NOW" is visible on the Time Line, indicating that thefile is open for appending (See FIG. 9), the icon depicting a note isdrawn at the "NOW" position.

The steps necessary for panning the contents of a Time Line areillustrated in the flow diagram of FIG. 14. The user can pan, or scrollin the horizontal dimension, the contents of the Time Line window toalter what is displayed. The display associated with panning is shown inFIG. 6. Panning can be achieved by clicking a panning tool on the TimeLine window and dragging it in the required direction, or by clicking onthe left or right scroll bar of the Time Line window.

Still referring to FIG. 14, the steps necessary to pan the Time Linedisplay are illustrated. When the Time Line display is panned, itscontents are redisplayed by first redrawing the scale and thendetermining whether the "START" appear on the display. If so, then"START" is redrawn. Next, the survey device determines whether thecurrent time is on the Time Line display and, if so, redraws "NOW" onthe Time Line display. Otherwise the query continues to determinewhether the files opened for appending. If the file is open forappending, then the time display along with the features and notes fromthe file are drawn on the display according to FIG. 18 discussed below.If the file is not open for appending, a query is taken to determinewhether "END" is on the Time Line. If "END" is on the Time Line, then itis redrawn. If "END" is not on the Time Line, then the features andnotes from the file are redrawn according to FIG. 18.

The user can alter the amount of time displayed in the Time Line windowby zooming in or out using zoom tools represented by icons. The stepsnecessary for zooming the Time Line are illustrated in the flow diagramof FIG. 15. To zoom in or out by a factor of 2, the user simply clicksthe appropriate zoom tool on the Time Line display. The point in theTime Line at which it is clicked will become the center of the zoomedTime Line window. To zoom in or out by a variable amount, the user canclick and drag along the Time Line. The resulting line determines eitherthe portion of the Time Line which should be visible after zooming in,or the length of the Time Line window into which its currently visiblecontents should be drawn after zooming out. The user can zoom the TimeLine window to display the full extents of the data file showing theentire contents from "Start" to "End"/"Now" using the a global zoomtool.

The user can specify the duration to be displayed, and also the mode inwhich the Time Line window should operate, via the "Scale Time Line"dialog. The display pertaining to scaling the timeline is illustrated inFIG. 8. The user can specify the time duration to be displayed in theTime Line window by filling in the "Duration" field. They can alsospecify whether, the Time Line window should first be automaticallypanned so that any selected feature or note will be visible. These itemscould be selected as the result of a search operation, or as a result ofselection in the map window or the Feature Editor. Second, they canspecify whether the Time Line window should automatically pan to theleft so as to keep the current point in time, i.e. "Now, on theright-hand-side of the window. Third, they can specify whether the TimeLine window should pan so that the start of the data file ("Start") isvisible on the left-hand-side of the window. Finally, they can specifywhether the Time Line window should pan to a particular point in time.

The user can select a feature or a note on the Time Line using aselection tool depicted by an icon. The steps required are illustratedin the flow diagram of FIG. 17. A selected feature is highlighted on theTime Line window, and also on the Map window if that window is open. Ifthe Feature Editor window is open when a feature is selected in the TimeLine window, then the Feature Editor will display the attributes of theselected feature for viewing, editing or deletion of the feature.Similarly, if the Feature Editor is used to step through features andnotes in the data file, the Map and Time Line windows will highlight thefeature/note currently displayed by the Feature Editor.

FIG. 12 illustrates the steps necessary to update the Time Line displayby adjusting the contents of the display. As time ticks by in theinternal clock of the survey device, the display must be updated. If thedisplay needs updating, the "NOW" indicator moves following the timescale as time passes. If a feature is being recorded, the features timebar continues until recording has been completed. Similarly, if a nestedfeature is being recorded, the nested features time bar is lengthened astime passes. Once a feature or nested feature has been recorded, theprocess ends. Also, if the Time Line needs to be panned, updating thedisplay required panning the Time Line according to FIG. 13 discussedbelow.

Referring to FIG. 13, the steps necessary to close a file areillustrated. In closing a file, the Time Line scale, the features fromthe Time Line scale display and the notes from the Time Line display areremoved respectively.

Referring to FIG. 17, the steps necessary to select a feature from themap display or feature editor are illustrated. When a feature isselected on the map display or in feature editor, the contents of theTime Line are redisplayed as follows. First, a determination is madewhether another feature is currently highlighted. If it is, the otherfeature is redrawn on the line. Otherwise, a query is made whether theselected feature is visible on the line. If not, a determination is madewhether the pan feature has been selected. If it has, then panning theTime Line is required according to the steps in FIG. 14 above.Otherwise, the process is ended. If the selected feature is visible onthe line, then the feature is highlighted on the line.

Referring now to FIG. 18, the steps necessary to draw a Time Linedisplay from a file are illustrated. Whenever the contents of a TimeLine display need to be redrawn, for example, as the result of opening afile, panning or zooming the Time Line display, the sequence ofoperations occur as follows. First, the survey display device goes tothe beginning of the file. Then the display device determines whetherthere are any features or notes remaining. If so, the next item is readin the file. If it is a note, then the survey device determines whetherthe note's time appears on the Time Line. If so, then the note icon isdrawn on the Time Line and the determination returns to whether anyfeatures or notes are left in the file. If it is not a note, then afeature is drawn from the file according to FIG. 19 discussed below.Once features or notes are no longer remaining, then the drawing of theTime Line from the file is completed.

Referring to FIG. 19, the steps necessary to draw a feature from a fileare illustrated. Whenever a feature which has been previously recordedneeds to be redrawn, for example, as a result of opening a file, panningor zooming the Time Line, the sequence of operations required occurs asfollows. First, the survey device determines whether the features startor end indicators appear on the Time Line. If not, the feature is notdrawn from the file. Otherwise, a time bar starting at the start of thefeature, or the left hand side of the Time Line window and ending at theend of the feature, or at the right hand side of the Time Line window isdrawn. Then if a point feature is indicated, the icon of the pointfeature is drawn. Similarly, if a line feature is indicated, a line isdrawn and if an area feature is indicated, a rectangle is drawn.

The Time Line and the Map window, illustrated in FIGS. 2 and 3respectively, and the Feature Editor provide different views of the samedata file. Each is dynamically updated as new features are recorded. TheMap window provides a spatial or geographical plan view of the datawhich is captured, while the Time Line and Feature Editor providechronological views of features and notes. The Feature Editor useschronological ordering merely as a convenient way to present theattribute information for each feature in turn, whereas the Time Line isa to-scale representation of the events which occurred, and continue tooccur, as features and notes are recorded.

Features which are displayed on the Time Line use the user-configuredicons for point features and user-configured colors for line and areafeatures. It is useful to display features the same icons and colors.This makes it easy to identify features of a particular type on both theMap and Time Line windows.

The Map, Time Line and Feature Editor windows are "synchronized" whichmakes it easy for users to search for features of interest in any or allof these windows. It is often easier to identify a particular feature inone of these windows than in another window. For example, the user mayknow that an attribute value was entered incorrectly for the lastcarrier-phase point feature, but may not be sure which feature this isthe Map window. Because carrier-phase point features require the user tolog data for a period of time, the user can easily see the feature ofinterest in the Time Line window with its "time bar" being quite long.The user can dick on this feature to select it in the Time Line. Thesurvey device software will automatically highlight that feature in theTime Line, Map and Feature Editor windows, so the user can see where thefeature is in the Map window and can edit its attributes in the FeatureEditor. The Time Line window makes it particularly easy to identifynested point features which cannot easily be identified in the Map orFeature Editor windows.

The embodiment of the present invention discussed above is a very usefulgeneral purpose GPS field survey tool. There are a number of possibleenhancements of this implementation which can make the Time Line windoweven more useful as a data viewing and analysis tool for differentapplications.

These enhancements center around the fact that, together with a timeaxis and captured features and notes, the Time Line window can also beused to display information about the GPS conditions which can prevailat the time these features and notes are recorded. The useful GPSinformation which could conceivably be displayed in the Time Line windoware set forth below.

The prevailing position dilution of precision (PDOP) information wouldbe very useful to an operator in the field performing a survey. PDOP isa heuristic from which an estimate can be made of the degradation inaccuracy of GPS positions due to satellite geometry. A high PDOP valueimplies reduced positional accuracy, while a low PDOP implies increasedpositional accuracy. The survey device can allow the user to electwhether or not to log PDOP information. An example is shown in FIG. 20.In the event that this information was, or is being, logged, the loggedPDOP values can be plotted on the Time Line. If PDOP information is notbeing logged, the survey device software can reconstruct an estimate ofthe prevailing PDOP values using the ephimerides for each satellite andthe record of which satellites are being used for position fixes at anypoint in time. This calculated value is likely to be identical to thelogged PDOP value except in the case of a malfunctioning GPS receiver oran irregularity in the GPS system itself.

The number of satellites being used to compute position fixes is oftenof interest. At any point in time, the survey device can tell whichsatellites were (are) being used to compute GPS positions, and canindicate this on the Time Line. An example of a Time Line window withthe number of satellites used for position fixes displayed is shown inFIG. 21.

The satellites which were being used for position fixes. At any point intime, the survey device can tell which satellites were (are) being usedfor computing GPS positions, and can indicate this on the Time Line. Theindication could merely note the satellite PRN numbers, or couldembellish this information by indicating the elevation of each satellitewhich is being used. Examples of a Time Line window with satellite PRNsand satellite elevations displayed as shown in FIGS. 22 and 23respectively.

In the presence of (real-time or post-processed) differentialcorrection, it is possible for a GPS receiver to compute heuristicprecision values, which are estimates of the accuracy of the GPSpositions currently being produced. These precision values can be loggedto provide quality assurance and quality control information to theeventual users of the captured data, or can be displayed to the user ofthe survey device field Software to allow him/her to ensure that eachfeature is captured to a required degree of accuracy. The precisionvalues take account of the PDOP heuristic, but also consider a wholerange of other factors, and in the presence of sufficient satellites theprecision heuristics are very reliable indicators. precision values aretypically displayed as horizontal and vertical components, in meters orfeet, but can be amalgamated into a single three-dimensional accuracyestimate. See FIG. 24 for an example of a Time Line window withprecision values displayed.

Without a doubt, there are other, more detailed and specialized positionsystem phenomena which might be displayed in the Time Line window. Thesewould tend to be more for technical support engineers to performsophisticated analysis and problem solving, whereas the suggestedenhancements listed above might be useful for typical users of thesurvey device Field Software. Of course, it is perfectly possible toimplement more than one of these enhancements, and possibly all of them,as the onedimensional nature of the Time Line window permits multiplestreams of time-ordered information to be displayed simply by increasingthe height of the Time Line window.

The survey device could also indicate on the Time Line the periods whenGPS positions were and were not logged. It could easily do so, bydrawing a trail of dots beneath the "time bar" of each feature. It couldalso indicate "not-in-feature" positions, that is, positions loggedbetween features.

It is important to appreciate that the display of GPS information suchas PDOP values and satellite numbers differs from GPS Mission Planningin one important sense. This is the fact that the information displayedon the survey device Time Line is what actually happened, whereas theinformation displayed by Mission Planning software is what willtheoretically will happen.

In most circumstances, Mission Planning software will be optimisticabout satellite visibility, and will therefore describe the satelliteswhich would seen in the absence of any obstructions. Mission Planningsuites such as the Trimble QuickPlan software allow a user to manuallyconstruct "curtains" which describe expected obstructions such asmountain ranges, but it is difficult to anticipate momentaryobstructions such as a passing truck, etc.

Of course, it is possible to blur the distinction between the GPSinformation which was logged as it was observed and the informationwhich might be observed in the near future. The Time Line could displaythe information which has been logged up until "Now", and could thenswitch to displaying calculated Mission Planning information. This wouldprovide the user with on-the-fly Mission Planning which could warn themof impending periods of high PDOP or poor satellite coverage. Adesirable implementation would show the theoretical or "best" PDOPvalues which would be achieved if all satellites above the currentelevation mask were visible, but should also show the "anticipated" PDOPwhich will be achieved using the current satellite constellation.

Thus, a novel method and apparatus of surveying using a surveyingapparatus with a user interface having a timeline display and a twodimensional map area display has been described. While the preferredembodiment of the surveying apparatus and method have been described indetail in connection with the figures, it should be understood that thedescription and figures are illustrative only and, as such, the presentinvention should only be limited in terms of the claims which follow.

What is claimed is:
 1. A data collection device comprising:a display; ameasurement data input configured to receive measurement data pertainingto an artifact for a duration of time; control logic configured toreceive measurement data from the measurement data input and display agraphical representation of the measurement data and the time durationon a timeline on the display, wherein the representation of themeasurement data is an icon.
 2. The data collection device as set forthin claim 1, wherein the type of the measurement data is a line feature,said measurement data represented by a line feature icon on the display.3. The data collection device as set forth in claim 1, wherein the typeof the measurement data is an area feature, said measurement datarepresented by an area feature icon on the display.
 4. The datacollection device as set forth in claim 1, wherein the type of themeasurement data is a point feature, said measurement data representedby a point feature icon on the display.
 5. A data collection devicecomprising:a display; a measurement data input configured to collectmeasurement data pertaining to an artifact to be measured; control logicconfigured to receive the measurement data and generate time basedinformation in response to a clock, the control logic configured toassociate an icon with the measurement data and to display the icon on atimeline on the display at a location on the timeline corresponding to atime indicated by the time based information.
 6. The data collectiondevice as set forth in claim 5, wherein the time based informationfurther indicates the duration of the measurement data, said controllogic further configured to display the duration of the measurement dataon the timeline.
 7. The data collection device as set forth in claim 5,further comprising an input to record notes, said control logic furtherdisplaying a note icon at a location on the timeline corresponding to atime of recording of the note.
 8. The data collection device as setforth in claim 5, wherein the control logic comprises a microprocessor.9. The data collection device as set forth in claim 5, wherein thedisplay further displays a map of the measurement data.
 10. The datacollection device as set forth in claim 9, wherein the control logicfurther is configured to enable the highlighting of an icon on thedisplay, said control logic further configured to highlight acorresponding portion of measurement data displayed on the map.
 11. Thedata collection device as set forth in claim 9, wherein the controllogic further is configured to enable the highlighting of a portion ofmeasurement data on the map on the display, said control logic furtherconfigured to highlight a corresponding icon displayed on the timeline.12. The data collection device as set forth in claim 5, wherein the typeof the measurement data is a line feature, said measurement datarepresented by a line feature icon on the display.
 13. The datacollection device as set forth in claim 5, wherein the type of themeasurement data is an area feature, said measurement data representedby an area feature icon on the display.
 14. The data collection deviceas set forth in claim 5, wherein the type of the measurement data is apoint feature, said measurement data represented by a point feature iconon the display.
 15. A method for collecting data comprising the stepsof:receiving measurement data; identifying measurement data by a timestamp; displaying a timeline and an icon representative of themeasurement data on the timeline at a location on the timelinecorresponding to a time indicated by the time stamp.
 16. The method asset forth in claim 15, wherein the method further comprises initiatingcollection of measurement data pertaining to a first artifact, said stepof receiving measurement data pertaining to the first artifact.
 17. Themethod as set forth in claim 16, wherein the method further comprisesthe steps of stopping the collection of measurement data when themeasurement data is of a predetermined a predefined accuracy anddisplaying a stop indicator on the time based display at the time thecollection is stopped.
 18. The method as set forth in claim 15, whereinthe icon is indicative of the accuracy within which the first artifactis measured.
 19. The method as set forth in claim 15, wherein the methodfurther comprises the steps of:generating geographical information usingthe received measurement data; and displaying a collection of generatedgeographical information.
 20. The method as set forth in claim 15,wherein the data comprises measurement data of features.
 21. The methodas set forth in claim 15, wherein the measurement data comprisesmeasurement data for different features, said steps of receiving,identifying, displaying a timeline and icon performed for a firstfeature, said method further comprising the interrupting receipt ofmeasurement data for the first feature to receive measurement data,identify measurement data and display a timeline and an icon for asecond feature, said step of receiving measurement data for the firstfeature resumed after receiving measurement data for the second feature.22. The method as set forth in claim 15, wherein the time stamp isindicative of the time duration of measurement data collected, said stepof displaying, displaying an indication on the timeline of the durationof the measurement data.
 23. The method as set forth in claim 15,further comprising the steps of:generating at least one moreconfiguration of the measurement data; and displaying in addition to thetimeline the at least one more configuration.
 24. The method as setforth in claim 23, further comprising the step ofenabling the highlightof a representation of measurement data; and automatically highlightingother representations of the measurement data when a representation ofmeasurement data is highlighted.
 25. A method for collecting measurementdata comprising the steps of:receiving measurement data for a firstfeature; prior to completion of receipt of measurement data for a firstfeature, halting the receipt of measurement data for a first feature andreceiving measurement data for a second feature; once receipt ofmeasurement data for a second feature is complete, completing receipt ofmeasurement data for the first feature.
 26. The method as set forth inclaim 25, wherein the first feature is a line feature and the secondfeature is a point feature.
 27. The method as set forth in claim 25,wherein the first feature is an area feature and the second feature is apoint feature.
 28. The method as set forth in claim 25, wherein thefirst and second features are selected from the group of area featuresand line features.
 29. The method as set forth in claim 25, furthercomprising the steps of displaying a timeline and icons representativeof the measurement data on the timeline corresponding to a timeindicated by a time stamp.